How to setup scene for Isometric workflow? In order to import 2D ISO image to make it in 3D
Step 01
Blend file - Dimetry

Set camera Dimetry (54.563/0/45) with dimension of your ISO-image
Increase camera dimension on Y axis *1.150
Add your image as Camera Background Image
Build your models and save

Step 02
Blend file - Isometry

Set camera Isometry (60/0/45)
Add Empty
Link Collection (or Scene) done in Dimetry
Parent link to Empty
Scale Empty on Z axis 0.81673
Render

Like that you can anytime to switch into correctly measured models in Dimetry, but just by opening Isometric file re-render for final output.